Exemplary embodiments of the invention relate to a method for controlling the operation of a centrifuge with a rotatable drum, in particular a separator or a decanter, in the centrifugal processing of a product, in particular in a clarifying of a product and/or in a separating of a product into different liquid phases with the drum.
Such methods are known per se from the prior art, thus from German patent document DE 100 24 412 Al or PCT International patent document WO 97/20634. German patent document DE 40 04 584 A1 discloses evaluating noise development of the centrifuge in the controlling of the separation process for optimization of the separation process.
With respect to this prior art, a further method is to be created for the operation of a centrifuge, which enables optimized modes of operation compared to the prior art.
According to an exemplary embodiment, in the controlling of the operation of the centrifuge the noise development of the centrifuge is controlled, by                a. at least one noise level limit being defined,        b. during operation, i.e., during a rotating of the drum of the centrifuge, the noise development of the centrifuge being measured by a sensor device,        c. the data measured by the sensor device being passed on to a control device, by which the measured data are compared to target data, and by which, using this comparison, at least one correcting variable is determined, and        d. with the control device, using the at least one correcting variable or using a plurality of correcting variables, the operation of the centrifuge is influenced so that the noise development does not exceed the at least one noise level limit.        
In such a way, the ongoing operation of the centrifuge is optimized in the centrifugal processing of a product, wherein the focus is not or only marginally an error detection, but rather a minimizing of the noise development as a function of at least one or more predetermined limits.
An optimization of the noise development as a function of predetermined noise development limits means, in particular, the reduction of the noise emission or respectively the reduction of the loudness of the centrifuge as a function of predetermined limits. Here, by way of example, the sound pressure level is named as a measurement. The sound pressure is measured here in μPa and is set in relation to a reference sound pressure level p0=20 μPa=2×10−5 Pa, so that it can be indicated in dB (decibels). Further conceivable physical values as a basis for the reduction of the sound intensity of the centrifuge are, however, also the sound power level (indicated in dB), the loudness (indicated in “sone”), the sound intensity in phon, or evaluated sound pressure—or respectively sound power level. The A-weighted sound level is based here, for example, in a frequency-dependent manner on human hearing with correction factors, in order to be able to better replicate the perceived sound intensity. The calculation of the total sound pressure level then takes place.
The sound pressure level Lp is calculated here according to the following formula:
Lp=20 log10 (p/p0) dB, wherein p stands for the measured pressure and p0 stands for the reference sound pressure level.
Example: Correction factors k for an A-weighted sound measurement:
Frequency [Hz]100200400100020004000800012000Correction−19.1−10.9−4.80+1.2+1.0−1.1−4.2factor k [dB]
The sum sound pressure level is calculated here according to the following formula:L=10×log 10 ((p12+P22+ . . . +pn2):(p02))
The invention is described in further detail below with reference to the drawings by means of an example embodiment.